The invention relates to a liquid-cooled high-load resistor.
DE 33 38 709 A1 discloses a liquid-cooled resistor in which a resistance wire is coiled around a ceramic molded component. This ceramic molded component has a platelike shape and protrusions on one plate surface. These protrusions guide the resistance wire more or less in one plane in a zigzag path. The other plate surface of the ceramic molded component is pressed against a heat sink in which flow channels run. Moreover, the resistance wire and the plate surface, on which the wire is deposited, are jointly coated with a glaze. This type of resistor does, in fact, have a low self-inductance, but is not capable of operating at high power levels that entail high losses.
German Utility Model Patent 91 00 865 discloses a liquid-cooled high-load resistor, which is comprised of a resistor element that is braced between two liquid heat sinks. An electrically insulating, heat-conducting disk is arranged between a liquid heat sink and the resistor element. The resistor element is comprised of an electrically insulating carrier member and a strip-shaped resistor material that is placed around one front end of the carrier member, so as to nearly cover the two flat sides of the carrier member. The resistor material in the area covered by the liquid heat sink is provided with slits, which allow the resistance value to be considerably increased per unit of length. Through this means, the power loss that is dissipated increases considerably. Since an electrically insulating, heat-conducting disk is provided between the resistor element and the liquid heat sink, the dielectric strength of this high-load resistor can be adapted to a desired insulating strength by properly dimensioning this disk. This liquid-cooled high-load resistor does, in fact, dissipate a high power loss in a small space, is low-inductive, and has a very high insulating strength. However, this liquid-coded high-load resistor consists of many individual components that are assembled at considerable expense.
German Utility Model Patent 91 11 719 discloses a liquid-cooled high-load resistor comprised of a housing and a resistor element. This resistor element is arranged within a chamber, which is traversed by the flow of a cooling liquid. This chamber is comprised of two insulating plates and one insulating ring. A doubly wound conductor-strip spiral is provided as a resistor element. The resistor element is braced between the two insulating plates in a way that allows the cooling liquid to flow through a rectangular channel. By configuring the resistor element directly in the pathway of the cooling liquid, so that the cooling liquid flows along on both sides of the current-carrying resistor element, a high power loss Can be dissipated by the cooling liquid. However, the use of a doubly wound conductor-strip spiral as the resistor element does not minimize the resultant inductance of the high-load resistor because of the geometry of a circular conductor. This resistor is neither simple to assemble, nor are its dimensions small.